We estimate the age of a site by calculating the years since the last fire. We then fit a curve to model the recovery of vegetation (measured using NDVI) as a function of it’s age. An additional level models the parameters of the negative exponential curve as a function of environmental variables. This means that sites with similar environmental conditions should have similar recovery curves.
The model was last fit on 2023-06-15 14:38:51.
This version of the model was fit with 54626 pixels including data from 2000-10-31 to 2014-06-26.
This repository was developed using the Targets framework.
── Attaching core tidyverse packages ────────────────────────
tidyverse 2.0.0 ── ✔ dplyr 1.1.0 ✔ readr 2.1.4 ✔ forcats 1.0.0 ✔ stringr
1.5.0 ✔ ggplot2 3.4.1 ✔ tibble 3.1.8 ✔ lubridate 1.9.2 ✔ tidyr 1.3.0 ✔
purrr 1.0.1
── Conflicts ──────────────────────────────────────────
tidyverse_conflicts() ── ✖ dplyr::filter() masks stats::filter() ✖
dplyr::lag() masks stats::lag() ℹ Use the conflicted package (http://conflicted.r-lib.org/) to force all conflicts to
become errors
Attaching package: ‘arrow’
The following object is masked from ‘package:lubridate’:
duration
The following object is masked from ‘package:utils’:
timestamp
Attaching package: ‘plotly’
The following object is masked from ‘package:arrow’:
schema
The following object is masked from ‘package:ggplot2’:
last_plot
The following object is masked from ‘package:stats’:
filter
The following object is masked from ‘package:graphics’:
layout
Loading required package: abind Loading required package: sf Linking to GEOS 3.10.2, GDAL 3.4.1, PROJ 8.2.1; sf_use_s2() is TRUE CmdStan path set to: /home/rstudio/.cmdstanr/cmdstan-2.31.0
These parameters represent the relationship of the following environmental variables to the recovery trajectory.
The plot below illustrates some example recovery trajectories. It currently just shows the top 20 cells with the most observations.
Compare estimated vs observed values for all pixels. This is not true validation - these pixels were included in the model fitting.
Maps of spatial parameters in the model.
See the links below for park-level reports on vegetation status.
Addo-Elephant_National_Park Agulhas_National_Park Bontebok_National_Park Garden_Route_National_Park Karoo_National_Park Namaqua_National_Park Richtersveld_National_Park Table_Mountain_National_Park Tankwa-Karoo_National_Park West_Coast_National_Park